Infiniti M45 (Y34). Manual - part 408

DTC P0340 CMP SENSOR (PHASE)

EC-321

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7. 

CHECK CMP SENSOR (PHASE) INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Disconnect ECM harness connector.

2.

Check harness continuity between ECM terminal 84 and CMP sensor (PHASE) terminal 2. 
Refer to Wiring Diagram.

3.

Also check harness for short to ground or short to power.

OK or NG

OK

>> GO TO 8.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

8. 

CHECK CAMSHAFT POSITION SENSOR (PHASE)

Refer to 

EC-321, "Component Inspection"

 .

OK or NG

OK

>> GO TO 9.

NG

>> Replace camshaft position sensor (PHASE).

9. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-132, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

ABS002JU

CAMSHAFT POSITION SENSOR (PHASE)

1.

Loosen the fixing bolt of the sensor.

2.

Disconnect camshaft position sensor (PHASE) harness connec-
tor.

3.

Remove the sensor.

4.

Visually check the sensor for chipping.

5.

Check resistance as shown in the figure.

Removal and Installation

ABS002JV

CAMSHAFT POSITION SENSOR (PHASE)

Refer to 

EM-38, "TIMING CHAIN"

 .

Continuity should exist.

PBIB0563E

Terminal No. (Polarity)

Resistance 

Ω

 [at 25

°

C (77

°

F)]

1 (+) - 2 (-)

Except 0 or 

∞

1 (+) - 3 (-)

2 (+) - 3 (-)

PBIB0564E

EC-322

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

PFP:20905

On Board Diagnosis Logic

ABS002JW

The ECM monitors the switching frequency ratio of heated oxygen
sensors 1 and 2.
A three way catalyst (Manifold) with high oxygen storage capacity
will indicate a low switching frequency of heated oxygen sensor 2.
As oxygen storage capacity decreases, the heated oxygen sensor 2
switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2
approaches a specified limit value, the three way catalyst (Manifold)
malfunction is diagnosed.
Malfunction is detected when three way catalyst (Manifold) does not
operate properly, three way catalyst (Manifold) does not have
enough oxygen storage capacity.

DTC Confirmation Procedure

ABS002JX

NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

 WITH CONSULT-II

TESTING CONDITION:
Do not hold engine speed for more than the specified minutes below.

1.

Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.

2.

Start engine and warm it up to the normal operating tempera-
ture.

3.

Turn ignition switch OFF and wait at least 10 seconds.

4.

Start engine and keep the engine speed between 3,500 and
4,000 rpm for at least 1 minute under no load.

5.

Let engine idle for 1 minute.

6.

Make sure that “COOLAN TEMP/S” indicates more than 70

°

C

(158

°

F).

If not, warm up engine and go to next step when “COOLAN
TEMP/S” indication reaches to 70

°

C (158

°

F).

7.

Open engine hood.

SEF484YF

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0420
0420
(Bank 1)

Catalyst system efficiency 
below threshold

●

Three way catalyst (Manifold) does not operate 
properly.

●

Three way catalyst (Manifold) does not have 
enough oxygen storage capacity.

●

Three way catalyst (Manifold)

●

Exhaust tube

●

Intake air leaks

●

Fuel injector

●

Fuel injector leaks

●

Spark plug

●

Improper ignition timing

P0430
0430
(Bank 2)

SEF174Y

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

EC-323

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8.

Select “DTC & SRT CONFIRMATION” then “SRT WORK SUP-
PORT” mode with CONSULT-II.

9.

Rev engine up to 2,000 to 3,000 rpm and hold it for 3 consecu-
tive minutes then release the accelerator pedal completely.
If “INCMP” of “CATALYST” changed to “CMPLT”, go to step 12.

10. Wait 5 seconds at idle.

11. Rev engine up to 2,000 to 3,000 rpm and maintain it until

“INCMP” of “CATALYST” changes to “CMPLT” (It will take
approximately 5 minutes).
If not “CMPLT”, stop engine and cool it down to less than 70

°

C

(158

°

F) and then retest from step 1.

12. Select “SELF-DIAG RESULTS” mode with CONSULT-II.

13. Confirm that the 1st trip DTC is not detected.

If the 1st trip DTC is detected, go to 

EC-324, "Diagnostic Proce-

dure"

 .

Overall Function Check

ABS002JY

Use this procedure to check the overall function of the three way catalyst 1. During this check, a 1st trip DTC
might not be confirmed.

CAUTION:

Always drive vehicle at a safe speed.

 WITH GST

1.

Start engine and warm it up to the normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for 1 minute under no load.

4.

Let engine idle for 1 minute.

5.

Set voltmeters probes between ECM terminals 114 [HO2S1
(bank 1) signal], 115 [HO2S1 (bank 2) signal] and ground, and
ECM terminals 123 [HO2S2 (bank 1) signal], 124 [HO2S2 (bank
2) signal] and ground.

6.

Keep engine speed at 2,000 rpm constant under no load.

SEF940Z

SEF941Z

SEF535Z

PBIB0063E

EC-324

DTC P0420, P0430 THREE WAY CATALYST FUNCTION

7.

Make sure that the voltage switching frequency (high & low)
between ECM terminals 123 and ground, or 124 and ground is
very less than that of ECM terminals 114 and ground, or 115 and
ground.
Switching frequency ratio = A/B
A: Heated oxygen sensor 2 voltage switching frequency
B: Heated oxygen sensor 1 voltage switching frequency
This ratio should be less than 0.75.
If the ratio is greater than above, it means three way catalyst
does not operate properly. Go to 

EC-324, "Diagnostic Proce-

dure"

 .

NOTE:
If the voltage at terminal 114 or 115 does not switch periodically more than 5 times within 10 seconds at step 5,
perform trouble diagnosis for DTC P0133, P0153 first. (See 

EC-224

 .)

Diagnostic Procedure

ABS002JZ

1. 

CHECK EXHAUST SYSTEM

Visually check exhaust tubes and muffler for dent.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace.

2. 

CHECK EXHAUST GAS LEAK

1.

Start engine and run it at idle.

2.

Listen for an exhaust gas leak before the three way catalyst (Manifold).

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace.

3. 

CHECK INTAKE AIR LEAK

Listen for an intake air leak after the mass air flow sensor.

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace.

PBIB0068E

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